Surveys for Hoplodactylus Aff. Granulatus, Roys Peak and Mt Alpha, Wanaka

Surveys for Hoplodactylus aff. granulatus, Roys Peak and Mt Alpha, Wanaka Mandy D Tocher Science & Research Unit Department of Conservation PO Box 5244 Dunedin Leigh J Marshall c/o Zoology Department University of Otago PO Box 56 Dunedin Published by Department of Conservation Head Office, PO Box 10-420 Wellington, New Zealand This report was commissioned by Otago Conservancy. ISSN 1171-9834 © 2001 Department of Conservation Reference to material in this report should be cited thus: Tocher, M.D.; Marshall, LJ, 2001. Surveys for Hoplodactylus aff. granulatus, Roys Peak and Mt Alpha, Wanaka. Conservation Advisory Science Notes 344, Department of Conservation, Wellington. Keywords: forest geckos, Hoplodactylus sp., search, Roys Peak, Wanaka Ecological District. 1. Introduction and background Recent evidence shows the forest gecko Hoplodactylus granulatus (sensu Thomas 1981) comprises at least two species (Hitchmough 1997). Based on allozyme data, Hitchmough (1997) has reinstated the cloudy gecko H. nebulosus from synonymy with H. granulatus. Furthermore, Hitchmough (1997) suggests there may be further undescribed species within the H. granulatus complex, but the small number of samples available for analyses prevents further subdivision. In particular, forest geckos from the North Is- land differ genetically from forest geckos of the South Island West Coast. In addition, forest geckos from Nelson/Marlborough are genetically similar to forest geckos from the South Island West Coast, but their life history traits are more similar to forest geckos from the North Island. Hitchmough (1997) also refers to other geckos that are likely to represent further undescribed species of H. granulatus type geckos. A small juvenile gecko from the Esperance Valley in Fiordland superficially resembles Hoplodactylus rakiurae, although it is thought to be morphologically quite distinct. Gecko specimens from Open Bay Island off the coast of Westland are soon to be de- scribed as a new species (A. Whitaker, pers. comm. 2000). Open Bay Island H. aff. granulatus have a distinct form, but share some characteristics of both H. nebulosus and H. granulatus (sensu stricto Hitchmough 1997). More recently, geckos collected from the Catlins, Otago, are distinct from both H. nebulosus and forest geckos found in Westland and the Esperance Valley (Tocher et al. 2000). A gecko found in the Takitimu Mountains in Southland appears closely affiliated with H. nebulosus (R. Hitchmough pers. comm. 2000). Finally, a distinct gecko was collected from the Denniston Plateau in Westland in early 1999. The identity of this animal still remains unknown (A.Whitaker, pers. comm. 2000). In February 1998, LM and RossThompson discovered a gecko under a rock on the summit of Roys Peak (1580 m a.s.l.), during a day tramp from Wanaka. The gecko was discovered on land leased from the Crown by the Police De- partment. The gecko was small (80 mm snout to vent length) and had brick red coloured markings on its back (Figure 1). Of particular significance, the gecko's mouth lining was bright orange, suggesting the specimen was a type of forest gecko rather than a common gecko of the Hoplodactylus maculatus complex (Hitchmough 1997). LM photographed the gecko and replaced it at the point of capture. After examining the photograph, MT organised the first of three expeditions to Roys Peak in March 1998 with the objectives: 1. To collect 1-2 specimens for genetic analyses in order to elucidate the taxonomy of the Roys Peak gecko. 2. To attempt to estimate the abundance, distribution and habitat prefer- ences of geckos from Roys Peak. Inclement weather resulted in no geckos being found during the first visit to Roys Peak. A second visit later in March 1998 also failed to find the elusive 1 Roys Peak gecko. During a third visit that was carried out during exceptional weather in January 1999, six Roys Peak geckos were found. The aim of this report is to document the two unsuccessful surveys to Roys Peak, and detail the third successful survey. We also discuss the taxonomy of the Roys Peak gecko. 2. Site description of Roys Peak and Mt Alpha Roys Peak and Mt Alpha are located south-west of the Wanaka township, and both overlook Lake Wanaka and the Mototapu Valley (Figure 2). The Roys Peak-Mt Alpha ridge forms part of a property boundary between the Alphaburn and Hillend pastoral leases (Figure 3). The ridge itself is on the Hillend property. The Crown leases the summit of Roys Peak to the Police Department, and communication towers on the peak are prominent landmarks of the Wanaka Area. The upper slopes of Roys Peak/Mt Alpha are steep and relatively unmodified, and have a snow cover for 3-4 months of the year. On the north-west slopes, tall and moderately dense Chionochloa rigida is prevalent, and there is a dense tussock litter layer. False spaniard Celmisia lyallii is the dominant tall inter-tussock species; while true spear grass (Aciphylla aurea) is sparsely scat- tered. At ground level, areas not covered in tussock litter have Pimelea oreophila, Leucopogon fraseri, Raoulia subsericea, and Lycopodium fastigiatum. Weeds are sparse. Dracophyllum pronum is the most common shrub and can be locally abundant (Barkla pers. comm.). Small rock outcrops and bluffs have shrubs of Helichrysum intermedium, Gaultheria crassa and Carmichaelia petrei. Other species include Pentachondra pumila, Raoulia australis, Wablenbergia albomarginata, Celmisia gracilenta, Geranium sessiliflorum, Epilobium sp., Rytidosperma setifolia and Colobanthus buchananii (Barkla pers. comm.). Below 1000 m, most of the land has been oversown and top-dressed and is much modified from its original tussock and native scrub or forest cover. Some beech forest remnants persist in the lower-altitude valleys. Much exposed rock is present in the vicinity of Roys Peak and Mt Alpha, but the rock shows evidence of recent disturbance by snow melt or freeze/thaw processes. The Roys Peak/Mt Alpha ridge has many large rock outcrops (Fig- ure 3) which are not well fissured, and provide no obvious retreat sites for lizards. Boulder fields are common on less steep slopes, but the boulders are usually wet underneath and thus unsuitable for gecko occupation. Small non- moving boulder piles are also present, in particular near the summit of Roys Peak. On the north-east slopes of Mt Alpha, a 0.25 ha area of large (>5 m x 5 m) boulders have fallen from the rock castles on the ridge of Mt Alpha and accu- 2 mulated in a depression. It was at this site that the majority of the Roys Peak geckos were located (Figure 3 and 4). This was the only area of this habitat type located during surveys. Sign of the Roys Peak gecko (sloughed skin remains) was also found in two very localised areas of rock slabs/boulder stacks (approx. 50 m x 80 m). In these areas, rocks mounted on rocks partially em- bedded into the ground provided deep and dry retreats for the Roys Peak gecko. 3. Surveys for Roys Peak geckos Both day and night surveys were carried out during all three surveys of Roys Peak. Day searches involved lifting rocks to search for geckos or their sign. Night searches were made using lights mounted on binoculars to detect gecko eye shine (see Whitaker 1994 for a full description of this method). For this report, grid references (expressed in New Zealand metric grid, NZMG) and altitude (m) are derived from the 1:50 000 topographical map series (NZMS) 260 sheet F40 (Wanaka). All lizards captured were sexed and checked for mites, bites and scars. Four of the six Roys Peak geckos that were found on the third survey were re- leased at the exact point of capture following their measurement. The capture site was temporarily marked with reflective tape and also by rock cairns. Two geckos were taken from the field and sent to Rod Hitchmough, Victoria University of Wellington, for him to determine their taxonomy. Prior to their release, four Roys Peak geckos were toe-clipped to obtain a genetic sample. Toes were removed using nail scissors sterilised between the clipping of different animals by wetting and flaming with ethanol. Toes were placed in 100% ethanol, and were also sent to Rod Hitchmough. Body measurements were made in the field on all animals caught. Snout-vent length (SVL) and vent-tail length (VTL) were measured using a ruler to the nearest 1 mm; weight was measured to the nearest 0.1 g using a PesolaTM spring balance. 3.1 SEARCH 1 8-9 March 1998 Survey members: Leigh Marshall, Mandy Tocher and David McFarlane. This first search for the Roys Peak gecko was severely hampered by bitterly cold and wet weather. Nevertheless, a brief period of day searching was carried out by lifting rocks in the vicinity of the original capture site (F40 969 051) on 8 March during wet, cold and windy weather. A night search in the same area was also attempted on the cold evening of 8 March. This search prima- rily had the goal of familiarising all party members with the technique of 3 searching for gecko eye reflections (Whitaker 1994). We used PentaxTM 12 x 50 mm binoculars with a mounted WinchesterTM head lamp, attempting to get the light beam as close as possible to the line of sight of the binoculars (one set of spotlighting equipment). The night was thick with cloud and visibility was less than 5 m. The air temperature was approximately 4°C as we left camp to begin the search, and it progressively dropped throughout the search. Day searching was continued on the morning of 9 March. The weather was cloudy during the morning search and visibility was low. The search concen- trated on the north-east face of Roys Peak and was continued at random stop- points near the track during our decent to the car park.

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